PETER Robinson has backed down on his threat to resign after the Prime Minister caved into pressure and promised an inquiry into "amnesty" letters sent to IRA suspects – pulling Northern Ireland back from the brink of political meltdown.

PETER Robinson has backed down on his threat to resign after the Prime Minister caved into pressure and promised an inquiry into "amnesty" letters sent to IRA suspects – pulling Northern Ireland back from the brink of political meltdown.

David Cameron announced there would be a judge-led probe into the arrangement that led to more than 180 letters being sent to on-the-run republicans.

Mr Cameron's pledge came hours before a midnight deadline set by the First Minister, who had warned he would quit unless a judicial inquiry was called and the letters rescinded.

The DUP leader's ultimatum followed the collapse of the trial of John Downey, suspected of involvement in the 1982 Hyde Park bombing which killed four soldiers.

At a hastily-arranged Press conference yesterday evening Mr Robinson confirmed he would be staying put.

He claimed assurances he received from the Government about the letters, advising on-the-run republicans they could return to Northern Ireland without fear of prosecution, had rendered them effectively "worthless".

"I am satisfied with the response that I've got from Government," he said.

"I think the Prime Minister and the Secretary of State have been prompt, they have dealt with the issue seriously and in the manner that is satisfactory to me.

"I do not intend to resign, on the basis that if you get what you want, why on Earth would you want to resign?"

However, there were claims the Prime Minister's announcement did not go far enough.

TUV leader Jim Allister said: "If Peter Robinson accepts what the Prime Minister has offered, then he will have buckled within 24 hours of playing the hardman."

Sinn Fein said the inquiry was unnecessary, branding it a "political fig leaf" to get the DUP off the hook.

Martin McGuinness tweeted: "Nothing that happened today undermines the status of the letters issued by the British Govt in what Brit Att Gen says was a lawful process."

A day of fast-moving political developments started with the Deputy First Minister insisting unionists were aware of a Government scheme to deal with the on-the-runs.

Later, at a Downing Street Press conference, Mr Cameron repeated his view that the Downey case had been a "terrible error", promising a judge-led review.

The judge will be given "full access to Government files and officials" and will report by May, Mr Cameron said.

Mr Cameron said it was important to set out the facts of what had happened. "When we came to power in 2010 we inherited a process where letters were sent setting out the factual position on whether or not some individuals were wanted for questioning by the police," he added.

"This process continued under this Government. There was never any amnesty or guarantee of immunity for anyone, and there isn't now."

He added: "It is right that we take swift action, but let us also remember that Northern Ireland has made great strides forward as a result of the peace process.

"It is vital that we deal properly with the events of the past but make sure this never undermines our determination to build a shared and prosperous future for the next generation so that we never again return to the horrors of the past."

As well as commissioning the review, the Government said it would be making clear to all those who had received a letter in the past that if evidence now existed, or emerged in the future, which linked them to an offence they could be questioned or prosecuted.

Secretary of State Theresa Villiers said: "No recipient of such a letter should be in any doubt that if evidence emerges in the future in connection with terrorist offences committed before the Belfast Agreement they will be liable for arrest and prosecution."

Mr Robinson claimed that move represented a fundamental change to how the scheme had operated before.

"I think that makes it clear that they have a fairly worthless piece of paper," he said.

He added: "I think there will be a lot of on-the-runs who will sleep less easy tonight."

Mr Robinson said he wanted to move on from the controversy.

"I hope that we can put this episode behind us," he added.

Sinn Fein said the last 72 hours had been "a manufactured crisis".

"It has already been made clear as recently as yesterday by the British Attorney General that the scheme in operation was lawful and proper," South Belfast MLA Alex Maskey said.

"Given that reality, I have to say I'm not sure what there is to inquire into.

"What cannot be challenged is the integrity of the scheme or the good faith of those who have been processed through it. These people have gone through a process and it has been established that they are not wanted for questioning or charge. That fact can't be changed.

"This announcement is a political fig leaf for the DUP to try and get them off the hook they jumped on to over the past few days."

Justice Minister David Ford welcomed the inquiry into the "misguided and secretive" scheme.

"It is critically important that this inquiry provides truth and transparency, and restores public confidence that the justice system treats everyone equally and fairly," he said.

Victims' campaigner Kenny Donaldson said the suggested parameters for the review were too limited.

"We demand that a public inquiry be held which would examine the full details of the political chess game that has been played since discussions – formal and back channel – first began between the Government and the republican movement," he said.

10 people believe to have received letters:

RITA O’HARE:

O’Hare is currently the General Secretary of Sinn Fein. She was arrested in Northern Ireland in 1972 for the attempted murder of British Army Warrant Officer Frazer Paton who was targeted in Belfast the previous year. O’Hare fled to Dublin while on bail. Following a three-year sentence for smuggling explosives to the IRA she was released in 1979.

LIAM AVERILL:

He escaped from the Maze while dressed as a woman in 1997. He had been serving life for shoting dead two Protestants in 1994. In 2000, while still on the run, he was awarded £5,000 by the European Court of Human Rights because he was not given a lawyer for 24 hours after his arrest.

CHARLES CAULFIELD:

Caulfield is said to be living in Monaghan.

He was named in the House of Commons by DUP MP Jeffrey Donaldson as being wanted in connection with the Enniskillen Poppy Day bombing which killed 11 people in 1987.

EIBHLIN GLENHOLMES:

He once topped the ‘most wanted’ list for suspected terror offences. In the 1980s, Glenholmes was at the centre of a high-profile extradition battle. She was wanted in Britain in connection with offences including murder, attempted murder, firearms and explosives. She was released by an Irish court, which concluded the extradition warrants were defective.

Glenholmes, who was never convicted of a terrorist offence, spent years on the run.

DERMOT FINUCANE:

Finucane masterminded the 38-man mass breakout from the Maze in 1983 along with his brother, Seamus. Had been serving 18 years for explosives offences. He initially fled to the US with Artt. Later arrested in Ireland and successfully fought extradition attempts. Brother of Pat Finucane, a solicitor, murdered in 1989.

POL BRENNAN:

He also escaped from the Maze in 1983.

Had been serving a 16-year sentence for possessing explosives. He fled to America and created a new identity, working as a carpenter in San Francisco. While there, he married an American woman. He was deported to Ireland in 2009.

KEVIN BARRY ARTT:

He escaped from the Maze during a mass IRA breakout in 1983. He had been convicted of the murder of the prison’s deputy governor, Albert Miles, who was gunned down in front of his wife. He fled to the US and was caught by the FBI in 1992.

Artt escaped extradition after the US ruled his claims of unfair conviction in Northern Ireland must be investigated before sending him back.

JAMES MONAGHAN:

The former Sinn Fein national executive member was sentenced to six years in 1976 for possession of rocket launchers. He escaped during a huge explosion at Dublin’s Special Criminal Court. In 2001 he was detained in Colombia. It was claimed he had been sharing bomb-making intelligence with Farc geurillas. He was found guilty of travelling on a false passport but fled and cannot be returned to Colombia.

NESSAN QUINLIVAN:

Was awaiting trial over a suspected IRA assassination plot when he escaped from HMP Brixton in 1991. Using a gun hidden in a shoe, he shot a passer-by. He was arrested in the Republic for firearms offences in 1993 and jailed for four years. He was released early in 1996 and successfully fought attempts to extradite him in 2000, arguing he would have been freed by July 2001 under terms of Belfast Agreement.

OWEN CARRON:

He was an election agent for IRA hunger striker Bobby Sands. Carron fled to the Republic after being caught in possession of an AK-47 rifle in 1986. He had been granted bail to contest a by-election in Fermanagh but fled when he lost. The Irish Supreme Court ruled he could not be extradited over a “political offence”. He went on to work as a builder and a teacher.